Telescoping gauge



Aug` 10, 1943- G. T. swlNNl-:Y

TELESCOPING GAUGE Filed Sept. 17. 1942 IN VEN TOR.

GEORGE T Sw/NNEY ATTORNEYS Patented Aug. 10, 1943 UNET@ STATES taires-r 'rELnscoriNG Genen s l George fr. swinney, "Los Angeles, Cain., assignee" to The L. S. Starrett Company, Atliol; Mass.,V a

corporation ofi-Massachusetts applicati@ september 17, isis, serial ne! 458,643 e i 2 ciaims. (ci. gemaal My present invention relates to lcertain improvements in telescoping gauges, and particularly those of the type or structure of the patent to` Starrett and Adell No. 905,110,0f November 2K4, 1908. j Y y Y "These gauges vhave been on the market since the date of the above-noted patent, and since its expiration have been `also produced by manufacturers other than the original assignee, in substantially its origin-alform.V ,l

In these commercialgauges the smaller telescoping member had on one side a longitudinal groove with abrupt ends into which the lock pin projected and acted as a stop. This has been the structure oi all makes with which I am familiar and was on the whole generally satisfactory, but I have discovered that it had the defect of confining the telescoping member against rotation so that wear came always along the same longitudinal lines and the abrupt ends of the groove tended to hammer the end of the lock pin laterally under the action of the expansion spring when the lock was released. My concept is of a free rotatability of the smaller slide leaving its surface smooth and capable of making and maintaining an accurate sliding nt.

As another and somewhat correlated improvement I make the'body of my head so that it is a coacting member and not a mere collar for attaching a handle as in the prior art.

One of the specific difficulties in the old gauges was that restricted space had seemingly limited its clamp tightener to a small threaded engagement with the body of the head portion. .This I have overcome by the use of a relatively shorter tightening rod of small diameter, but held against buckling in a close tting bore, and by providing the zone of the binding screw engagement at the central or middle portion of the handle where its threads can be made of greater size and area.

These and other features of improvement will more fully appear from the drawing andthe description hereinafter set forth.

In the accompanying drawing I have shown a gauge improved according to my invention, which is simple to manufacture, yet overcomes the weaknesses supposedly` inherent in this type of gauge. In the drawing: Y

Fig. l is a side elevation of one of my improved gauges complete.

Fig. 2 shows the same in partial longitudinal section.

Fig. 3 is a view of the binding screw member, removedJ with its tightening rod.

Fig.v 4 shows on slightly larger scale the gauge in iurthervertical section, and n Fig. isga similar section to that of Fig.f4 but transversely at right angles to itsrplane.

V,The body l-'of the gauge is preferably of sphere icalor ball contour where the 'shankportion- 2 joins it,Y making the sofcalled VT-joint KAor sectionto which isattached the handleg carrying an axial Ybinding screw :piece havingafknurled knob 6. Y -AXially of the Yball shapedjoodyl I end 5 andan inner-bore 6. Y'

The itubularaplun'ger 1V has afcl-osi-zdfendffl"r which in use acts as a contact face opposite to".`

that of the hollow fixed anvil into which its opfposite or inner endk is Vguided with a free t by` l Y the close sliding fit of the exterior of the plunger f 1 in the bearing portion |92 ofthe bore lll. The bore l5 is shouldered at i9 and threaded between the shoulder Vto receive ther externally threaded open end 52 of the fixed anvil 5.

The open end of the tubular plunger l'has an iexternal shoulder I2 forming a stop to limit the outward motion of the plunger by contact withk for the slender tightening rod 9 without weak` ening the handle end. According to my inventionthe end of the handle 3 is reduced andV interior threaded for engagement with the threads 2 tion 3. that end of the handle 3 is a closely tted guide bore 8 slidablysupporting against buckling tencf the hollow end of the, shankpordency the slender kti'glltening rod 9 carried by the' binding screw piece d.

From the end opposite the guide bore 3 rthe 'I handle 3 is axially counterbored and threaded to form a receiving chamber having walls kof subthe rod 9 is iiXed. This allows `for sturdy threads in a large area of engagement generallyA midway the length of the handle for coopera tion with those of the threaded end 42`of thev I binding piece i when it is tightened by its 3.26am i* protrae a borelilgin oneend oi ywhich y is'threadeda sta'-l tion'ary cup-like' anvil 5 having a VclosedlcontactV Axially through it and part way along J knurled knob 4 to force the end of the rod 9 s against the surface of the plunger 'l to lock it in any position it may assume in axial adjustment. While the rod 9 is of relatively small diameter and of` considerable necessary length due to the novel positioning of the binding screw, it is held against any tendency to buckle by its location in the guide bore 8. Its f ree endis hard and makes direct contact with the outside of the plunger I when forced up against it by the binding screw 42. Y

As best seen in Fig. 4, I`interpose between the interior of the end of the xed anvil 5 and the interior end of the tubular plunger 'l a coiled wire compression spring H having a usual guide pin Il'. The coils are of a diameter to fit freely within the telescopic slide 1` and hence have full clearance in the larger diametered axial bore l5 of the fixed anvil 5. The spring I I may be compressed when the slide is being telescoped for entry into a hole or slot to be measured and locked in that condition until the gauge is properly positioned and then freed by turning back the knob 4 to release the tightening rod 9 and free the slide to make contact With the work'being mealsured. After this the telescopic slide may be again lockedprior to removalfor measurement withan outside micrometer capable of readings of great accuracy according to the established practice.

Certain modifications lin the details of parts may obviously be madewithout departing from thevspirit of my invention andthe combinations of the details of the several parts may be variously made as indicated in the appended claims.

What I therefore claim and desire to secure Y by Letters Patent is:

1. In a telescoping gauge, a body having a bore, an interior shoulder formed about the bore wall at one end, a tubular plunger having a sliding fit in said bore and having a closed contact end and an externallyrshouldered opposite end slidably engageable with said interior shoulder of the body bore, a hollow stationary anvial having a closedcontact end andan opposite open end at the Vend of Ysaid body bore and of an internal diameter freely receptive of the shouldered open rend ofY said plunger, and a compression spring disposed in the interiors of the plunger and said Ystationary anvil.

end and an opposite end at the end of said body bore and of an internal diameter` freely receptive of the shouldered open end of said plunger, and externally threaded at its open end and engaging said internally'threaded bore below said shoulder, and a compression spring disposed inthe interiors of the plunger and said stationary anvil.

' GEORGE T. SWINNEY. 

